Key to genera of Sematophyllaceae in Africa

Updated from: O'Shea, B.J. 1999. African Sematophyllaceae (Bryopsida) and a new key to the genera, using mainly gametophytic characters. Bryobrothera 5: 299-302.

1	Branch leaf cells smooth, without papillae (check several leaves, young and old, and look along a folded edge)	2
	Branch leaf cells papillose [key of Buck & Tan, 1989]	17
2	Dimorphic leaves (stem vs. branch)	3
	Monomorphic leaves (stem and branch leaves ± the same)	5
3	Nerve strong and double	*Wijkiella kenyae*
	Nerve absent or faint	4
4	Alar cells all about the same size	*Heterophyllium*
	Alar area with different sized cells	*Wijkia*
5	Alar cells not swollen	6
	Some alar cells swollen	7
6	Leaves short, often less than 1 mm, lanceolate, endostome segments blunt and short, fugaceous	*Gammiella ceylonensis*
	Leaves larger, c. 1.5 mm, ovate-lanceolate, acuminate, endostome much longer than exostome	*Macrohymenium*
7	Alar cells pointing inwards towards the stem, sometimes almost approaching 90°	8
	Alar cells straight, aligned along the leaf length	9
8	Leaves abruptly tapering to long loriform (parallel-sided) apiculus	*Rhaphidostichum gracile*
	Without loriform apiculus	*Acroporium*
9	Alar cells very thick-walled	10
	Alar cells thin- or firm-walled	11
10	Filiform propagules usually present, leaves wider (<5:1)	*Clastobryella pusilla*
	Propagules absent, leaves very long and narrow (7-8:1), usually twisted	*Clastobryophilum bogoricum*
11	Abruptly loriform (narrow, parallel-sided) apex to leaf	*Rhaphidostichum gracile*
	Leaf apex not loriform	12
12	Leaf toothed strongly, with thick-celled border towards apex	*Trismegistia*
	Leaf toothed or not, but with no border	13
13	Branch leaves diverse, peristome single	*Meiothecium*
	Branch leaves all similar, peristome double	14
14	Leaves longly and sometimes abruptly apiculate	*Rhaphidorrhynchium*
	Leaves without long apiculus	15
15	Peristome bone-white	*Donnellia*
	Peristome yellow	16
16	Leaves ovate, or if ovate-lanceolate, then narrowing into the apex	*Sematophyllum*
	Leaves ovate-lanceolate with a gradual transition into the apex	*Trichosteleum*
17	Leaf cells pluripapillose, often almost to base	*Radulina borbonica*
	Leaf cells unipapillose, basal cells smooth	18
18	Alar cells thick-walled, sometimes with the lumina narrower than the walls; leaves falcate-secund, exothecial cells not or obscurely collenchymatous	*Warburgiella leprorrhyncha*
	Alar cells thin- to firm-walled, the lumina much wider than the walls, leaves falcate or straight, sometimes complanate, exothecial cells collenchymatous or, if not, then operculum conic-rostrate	19
19	Leaves oblong, strongly concave, often strongly ranked, not constricted at the base, with apex obtuse, acute to shortly acuminate, cells papillose only in the upper half of leaves	*Papillidiopsis*
	Leaves ovate to lanceolate, complanate, falcate to slightly concave, evenly spaced on stems, constricted at base, with apex usually long-acuminate, cells papillose in upper 2/3-3/4 of leaves	20
20	Leaf cells ± linear, exothecial cells collenchymatous, operculum long-rostrate	*Trichosteleum*
	Leaf cells mostly 3-4:1, exothecial cells not collenchymatous, thin-walled, operculum conic-rostrate	*Acanthorrhynchium papillatum*